Add else clause to pattern-match assertions in DestinationCollisionResolverTests

[bguidolim]

Problem

In DestinationCollisionResolverTests, the if case let .copyPackFile(_, destination, _) pattern-match blocks silently succeed if the install action is not .copyPackFile. If the resolver erroneously changed a component's install action type, the assertion would never execute and the test would pass.

Example

// Current — silently passes if installAction is not .copyPackFile
if case let .copyPackFile(_, destination, _) = result[0].components[0].installAction {
    #expect(destination == "lint.sh")
}

// Improved — fails explicitly
if case let .copyPackFile(_, destination, _) = result[0].components[0].installAction {
    #expect(destination == "lint.sh")
} else {
    Issue.record("Expected .copyPackFile action")
}

This pattern is already used in ExternalPackAdapterTests.swift (lines 162-164).

Scope

All 7 test methods in DestinationCollisionResolverTests.swift use this pattern — each needs the else { Issue.record(...) } clause added.

References

• Tests/MCSTests/DestinationCollisionResolverTests.swift
• Tests/MCSTests/ExternalPackAdapterTests.swift — existing pattern to follow